Explosion Characteristics and Thermal Oxidation Behavior of Al-Li Alloy Dust Clouds with Different Micron Particle Sizes

To investigate the effect of the size of Al-Li alloy dust on the explosion behavior and underlying mechanisms, spherical powders (2.3 wt % Li) with median diameters (D50) of 9.9,30.8 and 48.5 μm were studied. The morphology, thermal oxidation performance and explosion parameters were evaluated by SEM, XRD, STA, Hartmann tube explosion test device and 20 L explosion test device. The experimental results show that the decrease of particle size significantly increases the severity and sensitivity of the explosion. Among them, the maximum explosion pressure (Pmax) increased by 28.6%, while the minimum ignition energy (MIE) decreased by 98%. Thermal analysis indicates that the exothermic reaction of small particles is more concentrated and advanced, with a lower apparent activation energy (303.02 kJ/mol). The analysis of explosion products shows that with the increase of particle size, the unreacted aluminum content increases, and the morphology changes from uniform spherical to irregular crack structure, reflecting the insufficient reaction inside the larger particles. Based on the above results, the mechanism model of Al-Li alloy dust explosion was established. This study quantifies the influence of particle size on explosion hazards, providing critical data and a theoretical framework for risk assessment and the formulation of safety protection standards in relevant industrial processes.